1) Field of the Invention
The present invention relates to a content billing method, and a content billing system and a content billing apparatus using the content billing method. In particular, the present invention relates to a content billing method for performing billing processing for digital content in which identification information is embedded by using a digital (electronic) watermarking technique on a computer, and a content billing system and a content billing apparatus using such a content billing method.
2) Description of the Related Art
Corresponding to the development in the computer technology and the widely spreading use of communication networks such as the Internet in recent years, exchange of high quality digital data through Internet connection equipment including a personal computer without deterioration of the digital data has been becoming increasingly easy. Accordingly, the extent of distribution of digital content such as programs, music, images, moving images, games, and the like has been becoming greater.
However, one feature of digital content is that copying, editing, delivery, and the like are easy. That is, digital content is vulnerable to unauthorized use by unauthenticated users. In order to protect copyrights of digital content in the above situation, in a current system, digital content is managed by embedding identification information in digital data based on a digital watermarking technique.
In addition, in order to prevent copying by users without permission, Japanese Unexamined Patent Publication, No. 2000-298689 discloses a management method, a management system, a recording apparatus, and a reproduction apparatus for digital literary works, in which the digital literary works are managed by embedding a route of use in digital content based on a digital watermarking technique.
Further, Japanese Unexamined Patent Publication, No. 2000-330873 discloses a content distribution system and a content distribution method, in which identification information is embedded in digital content based on a digital watermarking technique. In this case, an unauthorized-outflow-monitoring center collects related data, and unauthenticated digital content is handled as unauthorizedly used digital content.
On the other hand, charges for use of digital content are usually made to only primary users since the aforementioned feature of the digital content makes post-purchase management difficult. Therefore, for example, contract terms are set so as to prohibit unauthorized conducts such as unauthorized editing or resale. In addition, digital content is encrypted, and copying and delivery of the encrypted digital content is permitted. In this case, a charge is made for an encryption key which is used for decoding the encrypted digital content when the digital content is used. Further, unauthorized use of digital content is monitored, and another charge is made for the unauthorized use. That is, various measures are taken so that a proper charge is paid.
However, in the conventional content billing systems which make a charge for use of digital content for protecting copyrights of the digital content, billing processing corresponding to various types of use of digital content is not performed.
According to the conventional techniques, it is difficult to keep track of various types of use of digital content after purchase, and charges are made to only primary users. In order to pay proper royalties to copyright owners, purchase prices are usually set on the higher side in consideration of various cases. For example, since it is impossible to recognize whether digital content is used permanently or temporarily, a higher purchase price is set on the assumption that the digital content is permanently used. In addition, in the case where a piece of digital content which has been purchased is required to be widely used in a company, it is necessary to perform a bothersome procedure, for example, for purchasing further copies of the digital content or changing a contract term so that copying is permitted.
Further, for the purpose of copyright protection or the like, an ID or password may be required to be input when a piece of digital content is used, where the ID or password is issued when the piece of digital content is purchased. However, in this case, the management of the ID or password is likely to become bothersome work, and use of service is limited. For example, only specific persons which are registered for the service can use the digital content.
As explained above, the conventional billing processing for digital content, which is performed in order to protect copyrights of the digital content, is fixed processing which is determined in consideration of various cases. That is, the conventional content billing processing is not flexible according to various types of use.